Archive image from page 402 of The Danish Ingolf-expedition (1899-1953). The Danish Ingolf-expedition danishingolfex4apt1a2daniuoft Year: 1899-1953 HCIIINOIDEA. II. gg It is a renuirkablc fact tliat in sonic of the IllaIl specimens only one tnl)cfoot is developed in the plates I. a. i and V. b. i; the posterior tubcfoot in these i)lates nnist then develop later on. I-'roni the -Sijecimen of 3''' (Fio;. 16) it appears that the first tnbefoot to develop is the inner one of the plates I. a. I, II. a. i, III. b. i then follows that of the plates I. b. i, II. b. i, i and lastlv the oute
Archive image from page 402 of The Danish Ingolf-expedition (1899-1953). The Danish Ingolf-expedition danishingolfex4apt1a2daniuoft Year: 1899-1953 HCIIINOIDEA. II. gg It is a renuirkablc fact tliat in sonic of the IllaIl specimens only one tnl)cfoot is developed in the plates I. a. i and V. b. i; the posterior tubcfoot in these i)lates nnist then develop later on. I-'roni the -Sijecimen of 3''' (Fio;. 16) it appears that the first tnbefoot to develop is the inner one of the plates I. a. I, II. a. i, III. b. i then follows that of the plates I. b. i, II. b. i, i and lastlv the outer tube-foot of the plates La. i, II. a. i, III. b. i It is also .seen there that the latter appears first in the plate III. b. i. In one si)ecinun 1 have found liolh tnbefeet developed in the plate I. a. I, only one in V. b. i. — Some of the jjlates in the outer series of the bivial ambulacra may want pores {otally; this may hold good also for one or two of the plates of the inner series between the proximal ones and those bearing the large subanal tubefeet (the 6th-- 9th plate). The apical system of the youngest specimen (Fig. 17) is quite in accordance with that described and figured in the best possible way by Loven for the more advanced stages studied bv him. It is extremely important to learn, how it is in the fullgrown ., as Loven holds its cthmophract» structure to be of very great systematic nnportance, a view not universalh- accepted, the numerous stages from an ethmophract to an ethmo- lytic condition figured b\' Gauthier' tending especially to show this feature to be of no primary systematic importance. As shown in Fig. 18 the a])ical system of the largest specimen is as ethmophract as that of the smallest si:)eci- mens, the madreporic plate does not separate the posterior genital plates. There are four genital jjores, with well developed, up to more than 3''' long, genital papillae. A few madreporic pores are found also in the left posteri
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Keywords: 1890, 1899-1953, archive, arctic_regions, book, bookauthor, bookdecade, bookpublisher, booksubject, bookyear, copenhagen_h_hagerup, danish_ingolf_expedition_1895_1896_, drawing, historical, history, illustration, image, k_benhavns_universitet_zoologisk_museum, marine_animals_arctic_regions, page, picture, print, reference, scientific_expeditions, vintage
